


You Forgot the Ketchup

by tropicalsans



Category: Undertale (Video Game)
Genre: Attempt at Humor, Established Relationship, Fluff and Smut, Other, Plot What Plot/Porn Without Plot, Reader-Insert, Semi-Public Sex, Skeleton Ghost Penis, Skeletons, they bone at grillby's
Language: English
Status: Completed
Published: 2015-12-10
Updated: 2015-12-10
Packaged: 2018-05-05 23:26:37
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 3,611
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/5394149
Author URL: https://archiveofourown.org/users/tropicalsans/pseuds/tropicalsans
Summary: <blockquote class="userstuff">
              <p>Your closing routine just got a lot more interesting by a surprise visit from your favorite skeletal boyfriend.</p>
            </blockquote>





	You Forgot the Ketchup

**Author's Note:**

> i haven't written fic in so long i was about to go ahead and call this a lemon. what can i say, i'm a pathetic skelefucker and proud of it. forgive any tense issues or anything else glaringly obvious, it's been a while.
> 
> reader has a vagina but no gendered pronouns are used.

It’s close to midnight and you’re finishing up all the dreadfully menial tasks that come with being a server. You love your job at Grillby’s, you really do, but closing wasn’t your favorite thing to do. Usually Grillby tries to stick around and help out, but he had to leave early, so you shrugged and told him it was no problem.

It wasn’t, but you hadn’t closed by yourself in a while and you forgot how long the whole damn process was when you only had one set of hands.

Sighing dramatically, you finish stacking up the last of the chairs and survey your domain. Cash was all counted up and stored, receipts were bundled together, the tables were wiped and the furniture cleaned and stacked. All you had to do now was turn out the lights, lock up and you were done.

You stretch your arms high to try and soothe some of that after-work tension. Your shoulders were always a bit stiff after a long shift. A massage and a good glass of wine would do wonders right about now. Or two. Or three. Or…

Before you could justify having an entire bottle to yourself, you spot a lone bottle of ketchup sitting out on the bar. Your eyes narrow. You could’ve sworn you put that away already. 

Chalking it up to the late hour and your rush to get the hell out of there, you go over and pick it up, only to see that it’s left an ugly ring on your already perfectly clean counter. It was an assault on the eyes, frankly, and you couldn’t let it stand. So you fish out a rag from the drawer underneath to wipe at it, reaching again for the ketchup at the same time. Instead of the bottle, your fingers just grasp at air.

You look up, frowning. Okay, it was definitely there -

“Looking for something?”

You shriek, jumping back and throwing your rag without looking. It landed with a dull slap against the grinning face of your entirely too smug boyfriend.

“Sans, you asshole!” You groan, pressing your hand to your chest. “You about gave me a heart attack.”

He snickered, peeling the rag off and tossing it back on the counter. “Just enjoying the music, sweetheart. “ When you give him a confused look, his grin widens. “You know I love to hear you scream.”

Your cheeks warm despite how ridiculously cheesy his response was. You two hadn’t been dating for very long, but it was almost scary how quickly Sans started to pick up on all your little tells. It was like a game to him, seeing how much he can make you flustered. Which, admittedly, didn’t take a whole lot.

Still blushing, you gather yourself, hastily grabbing the rag and scrubbing at the mark, not meeting his eyes. You knew he’d have an even more shit-eating grin on his face from making you so embarrassed, and a person could only take so much humiliation in one night. You hear a creak as he settles on the bar stool.

“So, how was work tonight?”

You happily latch on to the topic change. “Pretty good! Made a decent amount of tips. Though you wouldn’t _believe_ the mess this one table made…”

As you emphatically relay your story of monster children running amok (with many a hand gesture and terrible voice impression to help), you take a moment to bend over to rewipe some of the drink nozzles behind the bar. Whatever response Sans had to the crucial plot point of your story trailed off as he suddenly became very quiet. You glance up, curious. The lights in his sockets were very focused on the way your shirt gaped open under your chest, his cheekbones turning blue.

You hold back your own self-satisfied smile as the wheels in your head began to turn. Here was your chance to get back at him, to get even for all the times he took advantage of how easily you got embarrassed with him. Sans was always so unshakable compared to you, teasing, hiding behind his grins and dirty jokes. 

The two of you have only danced around the topic of sex, neither of you quite bold enough to make the final move. Not from lack of wanting. There were plenty of nights spent tangled in your sheets with only your hand for company, stifling moans with your other and wishing Sans could be there with you.

Honestly, you were surprised you even mustered up the courage to tell him you were interested in the first place. Without some moral support from your friends (and some shots on the house from Grillby), you’d probably still be woefully single right now.

Not taking advantage of this opportunity would be a waste, you assure yourself.

You adjust your angle a bit, acting like you were very involved in the hose you were cleaning. From where Sans was sitting, you knew he had more than just a peek down your shirt. He could probably see your entire chest with how loose your shirt was, and you privately commend yourself on wearing your nice bra today. It presses invitingly tight against the swell of your breasts, enhancing the natural fullness. How fortunate for you, and hopefully for Sans.

Still bent over, you innocently look up at him, pausing from your cleaning. “What’s up, Sans? You got pretty quiet.”

He was very flushed at this point, not quite meeting your eyes. His grin seemed a bit strained. “I think you know exactly what’s up, _tibia_ honest.”

“Really? ‘Cause the only thing I want to see _up_ right now is your d-dick”

Fuck. You inwardly cringe. Leave it to you to stutter at the most crucial part.

Except wait, shit, does he even have a dick? 

Your stomach drops. Oh no. What if you just made a horrible mistake? He’s a skeleton for god’s sake, how could that even work? What if instead of your stupid line being a come-on, it’s completely a turn-off because now he thinks he needs one to make you happy, when honestly you’d be perfectly fine with his bony fingers shoved up anywhere in your body, just as long as they were inside you, but now you’ve gone and ruined…!

Now completely hunched over, your forehead pressed against your knees, you hide behind the bar and continue to agonize over your assumption. You’re so busy beating yourself up that you don’t even notice that Sans has hopped off the barstool. It’s when you feel a hand on your shoulder that you whip your head around.

There he was, crouched right next to you. When he sees he has your attention he winks salaciously. “If you wanted to see my boner, all you had to do was ask.”

You gape. Then laugh. Loudly. Then his hand is on your knee and you suddenly forget to breathe.

“I’m serious ya know.” His voice gets quieter, sincere. “That was one of the cutest things I’ve ever seen.”

You snort. “I was going for more ‘sexy’, but thanks.”

He squeezes your knee. “Definitely didn’t say it wasn’t that. In fact,” he leans closer, his voice slowing to a drawl. “I’ve wanted to bend you over this bar the minute I walked in here.”

The words hit you like a bolt of lightning. Suddenly the air between you got a little more hot, a little more tense. It’s quiet. You can hear your heart hammering away in your ears and the distant sound of wind from outside. 

You swallow. When did you guys stand up? All you can do is stare, hands now cradled in his, your face on fire, his bathed in the glow of the soft light overhead. You want him so badly it aches.

So you tell him.

“Why don’t you?”

His bones shiver, just slightly, before he’s pinning you against the counter, his mouth swallowing your gasp. It only takes a moment for you to melt against him. Your hands reach up to cup his jaw, pulling him hard against your lips. You can’t get enough. All you want is him touching you everywhere, _now_.

One of his hands slips under your thighs, his hard fingers lifting your leg up so that it was wrapped around his pelvis. The other dips under your shirt, running over your collarbones, almost reverently. His fingers feel cool against your heated skin. You shiver and his grin somehow grows wider, turning his head so his teeth bump against the corner of your mouth.

“What’s up babe? Not gonna get _cold_ feet are ya?”

“With how long I’ve wanted to get into your pants?” You punctuate with a roll of your hips against his and smirk. “‘ _Snow_ way.”

He freezes, his hands flying to your hips. You chuckle and mouth along his jaw, following the line down until you get to his neck. You take the time to suck along each and every vertebrae , tugging the zipper of his jacket down so you can slip your hands along his body. Now he’s the one shaking with want, his fingers squeezing your skin harder with every swipe of your tongue over his bones.

“Hey now, babe,” he groans, voice husky. You hum lightly, leaving wet kisses on his clavicle now. “As much as I’m enjoying this, you sure you wanna keep going here?”

Your brain feels so fuzzy it takes you a second to wonder what the issue is. That’s when you remember that you two were still in Grillby’s, your body still pinned against the bar, for all intents and purposes about to finally fuck your boyfriend. You whip your head around to look behind you. It was late enough that you doubt anyone would be walking around outside, but the threat was still there.

To your surprise, the thought of someone seeing you guys makes you even more turned on.

Heat rushes to your core, so much so that your legs almost buckle underneath you. If Sans wasn’t supporting your weight, you probably would’ve ended up on the floor. Instead your body is draped against his, your blood thrumming underneath your skin. You lean forward to where his ear would be, lips brushing against his cheekbone along the way.

“I want you to fuck me, right on this counter.”

It’s still for a moment. Then he’s lifting you fully on the bar, pressing his face into your neck and chuckling. “Sweetheart, you’re gonna kill me.”

You were about to fire back some kind of joke about him already being dead, but then he starts nipping and scraping along your neck and suddenly you’re the one who can’t breathe. You hiss, clinging at his shoulder blades through his jacket, your hips grinding against his on their own. The distinct heat and pressure you feel in return is a pleasant surprise.

Leaning back, your whole lower half practically squirming at this point, you purr, “So you _do_ have a dick.”

He responds by rolling his hips into yours. The hardness of what was definitely some kind of appendage in his pants feels fantastic, a rush of arousal racing through you. You weren’t expecting a dick. You weren’t sure _what_ you were expecting to happen when the two of you finally hooked up, but you hope the good surprises keep on coming.

“I can do a lot of tricks with it too, if you let me.” Sans grinds his hips into yours again, and you decide that you two have to move a lot faster, right now.

“Show me,” you breathe. His eyes have gone completely black at the tone of your voice, his hands shaking slightly at your hips. As if every last vestige of his control was unraveling. All because of you.

You slip your hands into his jacket again. Your fingers hook through his ribs and his whole body jolts, his hands squeezing so hard you know you’re going to have bruises later. 

Then he’s kissing you harder now, frantic. You can’t help but moan, licking into his mouth until he yields, running your tongue along every bit of teeth you can reach. You guys have kissed plenty, but _never_ like this, never so desperate.

His hand jerks forward, quickly fiddling with the button of your jeans before slipping inside. You gasp, your back arching off the bar and into his chest. He laughs throatily against your hair.

“You’re soaking,” he murmurs. You can only whimper in response. The shock of his cool, bony fingers against your heat feels better than you could ever imagine. His thumb brushes languidly against your clit and your whole body is drawn tight with the shock of it. Your chest is pressed hard against his until you suddenly decide your jeans need to be off, _now_.

You wriggle until he gets the hint, withdrawing his hand so you can hurriedly peel your jeans off. They land in a heap on the floor. You don’t care; the only thing you need is Sans touching you more. His fingers press against your folds through your underwear and you’re practically gasping, shamelessly grinding your cunt so you can feel more pressure, more friction.

“Sans, quit being such a tease,” you groan. He flutters his fingers against you and you roll your eyes. “Sans.”

“So impatient. It’s like we’re going to fuck for the first time or something.”

He tries to sound smug, but you can hear a note of breathlessness in his voice, sweat beading near his forehead. The thought of him becoming undone because of you, just from touching you, makes you feel so warm you feel like you’re floating. 

You decide it’s time to check out the whole package.

You stick your hand down his pants and Sans hisses a breath, his mouth open. What you touch feels so warm. Much warmer than what you expected, and your experimental squeeze has him bucking into your hand.

“ _Babe_ ,” he says. You grin into his shoulder.

“Now who’s impatient,” you whisper. Your fingers tentatively stroke along his length, the angle awkward but you’re just so curious. He feels nice and heavy in your hand. Your thumb swipes over his head and his whole body quakes. You’re about to do a little more before he grabs your wrist, pulling your hand out.

Worried you did something wrong, you open your mouth to say something but he quickly shakes his head. One of his eyes is sparking blue and he smiles sheepishly. “You’re fantastic, but I’m gonna blow if you keep that up.”

“Then please…” You toy with the edge of your underwear, gazing up at him through your lashes. His pelvis stutters, almost pressing forward into you, his expression so stricken you almost feel bad.

“Sweetheart, are you sure? We don’t have to do this here…”

You shake your head quickly. “I’ve been waiting too long for this, Sans.” You giggle, almost hysterically. “Don’t tell Grillby.”

He huffs out a laugh, pressing his mouth to your forehead in an affectionate kiss. Then his fingers are hooked into your underwear and pulling them off, tossing them somewhere behind him. You barely have a moment to think about how exposed you are in front of him before he’s pushing two of his fingers inside your clenching heat. 

“Shit…!”

He curls them inside of you, rubbing against your walls. Your thighs fall open as wide as they can go, your bare legs still wrapped around his hips. Just his simple touch made waves of heat crash through you, every thrust of his fingers making your body draw tighter and tighter. Your arms wrap around his neck, pulling him as close as he can get, and you make a low noise. He chuckles. 

“I think you can do better than that.” His other hand starts to rub tight circles against your clit and your mouth falls open in a broken whine, your hands clenched in his hood. It’s too much, so much at once. You start to fall apart, your orgasm rushing through you so hard and fast it almost hurts with the sheer pleasure of it. You keen, shaking, Sans continuing to draw it out as his hard fingers still work against you, keeping the aftershocks going long after they should have ended.

You feel like your whole body is one gigantic puddle. Vaguely, you can feel the bar’s nozzles pressing into your lower back, the counter hard underneath your ass, but you just feel so good none of it matters.

Sans swears and you blink dazedly up at him. He’s staring at you, the intensity of his expression offset by how blue his face is. “God, you’re just so beautiful. Seeing your face like that…”

He shudders. You lift your hand, fingers grazing his temple, and he turns his head to brush a kiss against your palm, breathing heavily.

The tenderness of the action makes your heart swell. You care for him so much, more than anyone else you’ve ever been with before. You want to fall apart in his arms, only his, over and over again.

You want more of him, right now.

“Sans,” you say, voice hoarse. His hips shift, pressing his hardness closer against you, and already you can feel heat building inside of you again, even more intensely than before. You need to feel his cock inside you, filling you.

You bend your legs towards you, toeing at his shorts. He freezes, just looking at you, before he gets the message and quickly wriggles out of his pants. His cock bobs as he does, and finally you get to have a good luck at him.

It’s blue. It makes sense, given how his magic appears. You don’t realize you’re staring so hard until he lightly coughs, scratching the back of his head.

“It, uh, ain’t gonna bite ya know.” Your eyes snap up to meet his. You’ve never seen him look so embarrassed before. As if he had anything to be embarrassed about.

“You’re gorgeous,” you say, and he flushes even more blue, if that was even possible. You lean forward to kiss him, hard, showing without words how much you appreciate everything about him. When you separate he trails after your mouth, his eyes half-lidded, the corners of his mouth lifting up in a smirk.

His smile disappears when you tilt your hips into his, the hot drag of his cock brushing against your opening and sending an electric thrill through your body. His hands are tight around your hips, soft flesh squeezing between his fingers. You swallow roughly and gently nudge his back with your ankles.

“Please Sans. We’ve both waited way too long for this.”

“You’re _patelling_ me.” 

You barely have a second to groan at his joke before he’s sinking into you, your voice catching harshly in your throat. He feels so big, almost too big, the pressure of him inside you radiating pleasure throughout your entire body. You suck in a breath, taking a moment to look down between your bodies, watching as he disappears inch by wonderful inch inside you.

You can feel the tremors from his body as he holds himself back, panting audibly. Soon he’s sunken completely inside you, the bones of his pelvis pressing into your hips, almost harsh but so uniquely Sans you relish every sensation of it. 

For a brief moment, it’s quiet. All you can hear is both of your breaths’ echoing inside the empty restaurant. You’re throbbing around him, body wound so tight it almost hurts.

Then he starts moving.

The drag of his cock pulling against your walls is heaven. His thrusts slowly build up in speed, each roll of his hips making him reach deeper inside of you. Your hand grasps at his shoulder, scrambling, the other gripping his hip bone to help pull him harder against you. One of his hands moves to cradle the back of your head, the tenderness of the action almost making tears gather at the corner of your eyes. 

You suck in a sobbing breath, your body coiling tighter and tighter. You lock eyes and his are so dark you can’t even see the pupils anymore. You can feel the controlled strength beneath his bones, holding back his full power, but just barely, his hips rocking into you again and again.

“Fuck, babe, you feel so good, you’re so good…!”

He presses his head into your shoulder, groaning. Beads of sweat trail down his skull. He reaches down to rub at your clit, hands shaking, and your back arches so quickly you slam against his ribs. The heat inside you reaches its peak as you come, screaming, your body falling apart in waves.

You’re so tight it doesn’t take Sans long to follow, his hips pounding until he stutters to a stop, groaning loudly. His release is hot inside you, the thought of him filling you almost makes you come again.

You both try to catch your breath. Sweat pools between your breasts and in the small of your back, but you’ve never felt more relaxed in your life. As your heart rate gradually slows, you sigh, tipping your head back, staring at the ceiling in a daze. You feel Sans’ fingers start to pet through your hair and you smile.

“We just fucked in Grillby’s.”

He chuckles into your neck. “We sure did. Think we’ll get celebratory drinks if we tell him?”

You gasp, slapping his shoulder. “You better not. I actually like this job.”

“Kidding, kidding. Though, if you didn’t have this job, you could always work with me at the hotdog stand…”

“Something tells me we wouldn’t get much work done.”

**Author's Note:**

> whew, that was fun. let me know what you think! i'm also over at tumblr at tropicalsans. as of writing this i've just made this account, so excuse the messiness, but feel free to send me any feedback or ideas over there too!


End file.
